Christopher Columbus
In the history of America, Christopher Columbus was, undoubtedly, one of the most important factors. Without Columbus, a rambunctious explorer set on finding a new way to trade spices with India, we would not have colonized the New World as early as we did. Columbus died not knowing the scale of his discovery, hence why today we call Native Americans "Indians", but he set the stage for years of colonization to come.
George Washington
The first President of the United States of America, George Washington was an important historical figure in the history of the country. Taking charge after the Revolutionary War in 1789, he brought a sense of security to the nation and set the foundation for what the ruler of a free and independent country should be.
Abraham Lincoln
Taking charge of the United States of America in the nineteenth century, Abraham Lincoln brought the country out of a difficult Civil War, and finally drew the lines for true equality of all of the country's citizens. Although the idea behind The Emancipation Proclamation that he drafted has not been completely followed up to this day, it showed that The United States can pull through even during the toughest of situations.
Martin Luther King Jr.
Bringing us very close to the modern day, Martin Luther King Jr. was an important civil rights activist. It was through his words that governments and people alike were persuaded to finally enforce equality amongst American citizens, and the egalitarian society that was perhaps the vision of America's Founding Fathers has been nearly achieved due to the actions of King and others like him.